/**
 * @author: TTDB
 * @create: 2025/10/17
 */
public class Q2 {
    //两数相加
    public ListNode addTwoNumbers(ListNode l1, ListNode l2) {
        ListNode dummy = new ListNode(-1);
        ListNode cur = dummy;
        int carry = 0;
        while(l1 != null || l2 != null || carry != 0){
            int sum = (l1 != null ? l1.val : 0) + (l2 != null ? l2.val : 0) + carry;
            carry = sum / 10;
            cur.next = new ListNode(sum % 10);
            cur = cur.next;
            if(l1 != null) l1 = l1.next;
            if(l2 != null) l2 = l2.next;
        }
        return dummy.next;

    }
    // 定义链表节点内部类
    static class ListNode {
        int val;
        ListNode next;

        ListNode() {}

        ListNode(int val) {
            this.val = val;
        }

        ListNode(int val, ListNode next) {
            this.val = val;
            this.next = next;
        }
    }
}
